life or death Tire Pressure question

[LD]

I have always heard that you should not fill the tires to the maximum pressure listed on the sidewall of the tire, but I am not sure where I heard that. He is filling his tires to like 44-45lbs and I usually fill mine to 33-35lbs. I told him he is putting too much air in because that is cold pressure and when it heats up the pressure will expand and cause it to go over the maximum. If anybody has any links to websites or any proof whatsoever that I can show him before he blows up his tires and kills himself please post it. Thanks

[ October 17, 2003: Message edited by: LD ]</p>

[Distephano]

Well, My door sticker says 30 PSI cold for front and back.

I filled them to that, and after roughly 9000 miles, I was noticing more wear in the center of the tire then the edges. So Now I backed it down to 28-29 PSI to get the tires to wear more even.

[LD]

<blockquote>quote:</font><hr>Originally posted by Distephano:
Well, My door sticker says 30 PSI cold for front and back.

I filled them to that, and after roughly 9000 miles, I was noticing more wear in the center of the tire then the edges. So Now I backed it down to 28-29 PSI to get the tires to wear more even.<hr></blockquote>

I'll have him check his door sticker, but he may not have one (1999 Ranger)

[V6Bob]

The tire shouldn't blow up (unless it's defective). The max tire pressure on the sidewall is max cold inflation pressure, not max pressure.

It's a bad idea because you'll get less traction, the center of the tire will wear out, and it will ride hard. If he's carrying a _big_ load in the bed it might be the thing to do for that trip.

If, for some reason, his door sticker has disappeared (he had one, maybe in the glovebox), the manual or a dealer can give him the correct tire pressure. He may even have more than one, for different loads.

[Knight5]

yeah if the tire pressure is above 40 in our cars it will ride like ****,I'll stick with 30 all around

[ October 22, 2003: Message edited by: Knight5 ]</p>

[JAM]

Folks do not go by your door sticker in the event a different brand of tire, or size has been put on.

Check the side wall. It will have a max inflation. Inflate to a few pounds under that amount. Example 45lbs inflate to 42. The extra few pounds allows for the expansion reffered too.

When in doubt it is better to over inflate than to under inflate. Under inflation is bad, and can be hazzardous.

Remeber just check the sizewall. Every brand, size, different compound etc is different somewhat.

My 2 cents... hope it helps.

;)

[V6Bob]

I disagree with that recommendation. While underinflation is hazardous, so is major overinflation.

See for yourself. Check out some cars with stock tires, the manufacturers tire sticker, and the max sidewall pressure. See how much you'd be overinflating the tires if you'd followed that recommendation on those cars.

If you did that you might be way overinflating aftermarket tires also. It's a crapshoot. Many tires have a max inflation pressure of 42 or 44. You'd be running fbodies around 40psi, which I think is way too much in most circumstances. There are tires with max pressure of 50-51, think high 40s could possibly be correct?

And changing between tire brands with the same size matters very little.

[ October 23, 2003: Message edited by: V6Bob ]</p>

[LD]

<blockquote>quote:</font><hr>Originally posted by V6Bob:
I disagree with that recommendation. While underinflation is hazardous, so is major overinflation.

See for yourself. Check out some cars with stock tires, the manufacturers tire sticker, and the max sidewall pressure. See how much you'd be overinflating the tires if you'd followed that recommendation on those cars.

If you did that you might be way overinflating aftermarket tires also. It's a crapshoot. Many tires have a max inflation pressure of 42 or 44. You'd be running fbodies around 40psi. There are tires with max pressure of 50-51, think high 40s could possibly be correct?

And changing between tire brands with the same size matters very little.<hr></blockquote>

do you have any websites or any info that can back this? I really can't show him a bunch of posts and convince him. I just really think 45 lbs cold is too much pressure for him to be running all the time.

[JAM]

I did not say to inflate to 45. I said the same thing V-6 bob said. He stated that if the max states 42 or 44 run 40lbs wich is about 4lbs less.

I was suggesting the same thing. Run a few pounds under what the max is. Example if your max reads 38lbs put in around 34-36.

[ravenp]

I've run mine all day at the track at 60 in the front and 50psi in the rear(due to a faulty guage) and i had no problems.. [img]smile.gif[/img]

I spun a bit but i had 3.08's then, so not too much [img]smile.gif[/img]

[LD]

<blockquote>quote:</font><hr>Originally posted by JAM:
I did not say to inflate to 45. I said the same thing V-6 bob said. He stated that if the max states 42 or 44 run 40lbs wich is about 4lbs less.

I was suggesting the same thing. Run a few pounds under what the max is. Example if your max reads 38lbs put in around 34-36.<hr></blockquote>

I know you didn't say run 45 lbs, I am saying he IS running 45 lbs
I guess if there is going to be no big problems then I won't mess with it anymore. Thanks for the info everyone

[V6Bob]

From:

http://www.gm.com/company/gmability/...ou/manual.html

"NOTICE: Don't let anyone tell you that underinflation or overinflation is all right. It's not. If your tires don't have enough air (underinflation), you can get the following:


Too much flexing
Too much heat
Tire overloading
Bad wear
Bad handling
Bad fuel economy.

If your tires have too much air (overinflation), you can get the following:


Unusual wear
Bad handling
Rough ride"

You can find more stuff like this by googling

overinflation tire safety

"I said the same thing V-6 bob said. He stated that if the max states 42 or 44 run 40lbs wich is about 4lbs less."

I trust everyone else realized that this was meant to illustrate that using the sidewall max was a _bad_ idea. I am definitely not suggesting running 40psi on an fbody. Way too much in most circumstances. I've edited the post to fix this.

[ October 23, 2003: Message edited by: V6Bob ]</p>

[Red2K1]

Basic Tire Pressure Info

[ October 29, 2003: Message edited by: Red2K1 ]</p>

[malice10985]

my 2 cents:

normal street driving: 30psi on all corners

Autocross/roadracing: 49psi front/47psi rear

drag racing: 30psi front/14psi rear

Those configurations treat me pretty well.